| 摘要 |
A synthetic quartz glass preform is produced by flame hydrolysis with subsequent cooling and is suitable for the application of high-energy DUV radiation in the wave length range under 250 nm. The preform has a core area which contains >=1150 ppm OH, a strain double refraction of <=5 nm/cm and a resistance to high-energy DUV radiation as a result of a transmission reduction of DELTAT<=0.1%/cm thickness. The quartz glass has been exposed to the following radiation: wavelength lambd1=248 nm, laser shot frequency>=300 Hz, laser shot value>=109 and lumination<=10 mJ/cm2, and wavelength lambd2=193 nm, laser shot frequency>=300 Hz, laser shot value>=109 and lumination<5 mJ/cm2. Apparatus for producing the preform comprises a horizontally positioned muffle with two different sized openings facing each other. The larger of the openings is for removing the preform, the smaller opening being for introducing a burner. The internal chamber of the muffle narrows from the larger opening to the smaller opening.
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